A 9.25 is a very stout rear, never broke one.
Dad bought a 78 power wagon new off the car carrier (still has it) beat the **** out of the old truck, it still runs with 250k miles, cover never off the rear.
I have a 78 power wagon with the same rear I pull a 3,000 camper with about another 1,000 lbs in the bed alot in the summer so it is holding up so far.
In my past I beat a 77 RamCharger hard, with 44" tires, rear held up fine.